Improvement in signal-boxes for fire-alarms



f placed.

UNITEDy STATES PATENT OFFICE.

CHARLES E. CARPENTER, OF PROVIDENCE, RHODE ISLAND.

IMPROVEMENTv lNrSlGNAL-BOXES FOR FIRE-ALARMS.

Specification forming part of Letters Patent No. 46,542, dated February28, 1865.

To all whom t 'may concern:

Be it known that 'I, CHARLES E. CARPEN- TER, of Providence, in thecounty of Providence and State of Rhode Island, have invented anImprovement in Electro-Magnetic Signal-Boxes; and I do herebydeclarethat the following is a full and exact description thereof,reference being had to the accompanying drawings, and to the letters andiigures marked thereon.

My improvement relates to the case or box within which the key-knob orlever is placed -that is used for making or breaking an electriccircuit, being intended for use in the electric lire-alarm system andfor other similar purposes.

. The boxes heretofore made have usually been provided with a cover ordoor that remains locked except when a signal is required to be,transmitted. The door orcover is then opened by means of a key, which iskept in the shop or room where the box is permanently As the key may berequired at any momentfor the purpose of unlocking the box, it iscommonly placed in a position thatis readily accessible. This is knownto many parties, and cases often occur in which unauthorized personsunlock the box and raise a false alarm of lire. After these alarms aregiven the boxes are all found closed and locked, and it is impossible todetermine from which box the alarm proceeded, the difficulty beingincreased by the fact that a large number of boxes are used in the city,town, or district. As a part of the regular routine of business of thelire department it is also desirable that the source of eachalarm-signal be positively known.

By the use of my improved signal-box the station or exact locali ty fromwhich the alarm proceeds is at once known without any possibility oferror.

. Figure I is a perspective view of the instrument. Fig. II is avertical section through the center of the box.

The box is represented at A, and the' cover or door at B. The line-wiresC and D pass through the box. Their ends or mechanism connected withthem are covered by a suitable case, J, and a hole through its centerallows the thumb-piece M N to pass downward and close or break thecircuit.

At the top of the box there is an aperture, E, about an inch indiameter, extending to the inside of the box, and across its mouth, atthis point, a sheet of paper, I, is placed. This is retained in positionby the circular washer or collar F, through the center of which there isa hole directly below the aperture E. This collar is held in contactwith the paper by means of the screws H and nuts G.

When a signal is to be made the linger is thrust into the hole E andthrough the paper I. It then rests upon the button or knob M,

which is depressed to close or break the circuit. As before mentioned,'the box remains locked and no access to the signal knob or key can behad, except by breaking the paper which forms a diaphragm across theaperture E.

h The key of the box is kept at the central station and is used only byan authorized attendant, who, after an alarm of tire has been given,opens the box and places a new piece of paper across the orifice.

To afford additional sccuritya peculiarkind of paper may be used uponwhich is an engraving or fancy design, as at S, Fig. II, or the papermay have a private markupon it, or a water-mark that can only be made bythe manufacturer of the paper.

What I claim, and desire to secure by Letters Patent, is-

A signal-box provided with an aperture to admit the linger, and having adiaphragm of paper or other suitable material extended across the' innermouth of the aperture, the position of the diaphragm being such that thesignal knob or lever cannot be moved without breaking the paper.

PETER D. GREENE, JOSEPH KELLY.

